Automatic punch press stopping mechanism



J1me 1954 R. J. ZAJIC 2,681,026

AUTOMATIC PUNCH PRESS STOPPING MECHANISM Filed May 17, 1951 2 Sheets-Sheet 1 5 52 1 :39 311 I WEE/56 'hlll H ng.

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lQczyrncoma7:J Z 'gI/ZC Patented June 15, 1954 OFFICE AUTOMATIC PUNCH PRESS STOPPING MECHANISM aymond J. zajic, C ica o. Il

Application May 17, 1951, Serial No. 226,770

1 Claim. 1

This invention relates to an automatic punch press stopping mechanism and is particularly concerned with an improved, hydraulically operated mechanism for automatically stopping the punch press immediately upon the jamming or misfeeding of the metal going through the die of the press.

In machines of the character herewith concerned, strips of material are inserted, individually, into a feedway provided in the machine and thereafter fed to the dies of the press where successive portions thereof may be worked upon with successive reciprocation of the press for stamping pieces therefrom. Said machines are adapted to be operated a stroke at a time or, if desired, the starting mechanism thereof may be depressed continuously thereby providing continuous operation of the machine at relatively high speeds. Occasionally, more than on strip of material is fed into the feedway or the dies whereupon it becomes necessary to sto the press and remove the extra strip of material. At other times a strip of material may buckle in the die or otherwise be warped or displaced whereby to jam inside the die. Unless the machine is stopped immediately before the next succeeding stroke thereof, great harm may occur to the press or valuable material may be wasted. It will be apparent that with the punch press operating at high speeds the occurrence of a jam or misfeed inside the die must be noted and corrected immediately so as to prevent such damage to the press and the wasting of expensive material, especially where the press is left unattended for substantial periods.

Accordingly, it is the principal object of this invention to provide automatic punch press stopping mechanism of the character described for stopping a press in the event of jamming or misfeeding of material inside the die upon one complete stroke of the press.

Another object of this invention is to provide an improved, hydraulicallyoperated mechanism for automatically stopping a punch press in the event material becomes jammed or is misfedin the die thereof, which mechanism is adapted for use either with manually operable or electrically actuated stopping and starting means of vthe press.

Still another object of the invention is to provide an improved, hydraulically operatedmechanism for automatically stopping a punch-press in the event of jamming or misfeeding of material in the die thereof, which mechanism is foolproof. highly reliable in operation, simple and .very efflcientinuse.

With the foregoing and other objects in view which will appear as the description proceeds, the invention consists of certain novel features of construction, arrangement and a combination of parts hereinafter fully described, illustrated in the accompanying drawings, and particularly pointed out in the appended claim, it being understood that various changes in the form, proportion, size and minor details of the structure may be made without departing from the spirit or sacrificing any of the advantages of the invention. V

For the purpose of ifacil-itating an understanding of this invention, there is illustrated in the accompanying drawings a preferred embodiment thereof, from an inspection of which, when considered in connection with the following description, this invention, its mode of construction,

assembly and operation, and many of its advantages should be readily understood and appreciated.

Referring to the drawings in which the same characters of reference areemplo-yed to indicate corresponding or similar parts throughout the e e a fi u e o h a n s:

Fig. -1 is a side elevational view of a punch press having my automatic unch press stopping mechanism associated therewith and having portions broken away to show certain operative details thereof.

Fig. 2 is a frontelevational view of a portion of a punch press having my invention associated therewith.

Fig. 3 a sectional View through the punch press taken along the line 3-3 .of Fig. 2 and in the direction indicated and showing in detail the automatic stopping mechanism embodying the n ent n Fig. 4 is a sectional view taken along the line 4-4 of Fig. .3 and in the direction indicated.

Fig. 5 is an elevational .view of electrical starting and stopping means for a punch press and showing the manner in which the automatic stopping mechanism embodying my invention may be-associated therewith.

The punch press to which the invention is ap d is desisn tedsene ell y h reference character 1-0 and may ,be of any suitable size and construction. Same includes a base ll upon which is mounted the punch press body I2 for supporting the various operating parts of the The press is operated in the conventional manner througharotating driving means including a flywheel I3 connected to a crank shaft (not shown) journalled in the upper portion of the body lZ. The flywheel I3 is connected to 3 the crank shaft through a clutch mechanism designated generally [4, the clutch I4 being of the one revolution type actuated by the rod l5. The lower end of the rod I5 is connected to a foot operated treadle [6 adapted to be actuated for starting and stopping the press. The treadle is pivotally mounted on the base II as at H and normally is biased upward by means of the spring i8 secured at one of its ends to a lug 19 on the base I i and at its other end to the lug 28 on the treadle. In this upward position of the treadle, the punch press is stopped. The upper end 2| of the rod is joined through suitable linkages 22 to the clutch mechanism I4.

The press l8 includes stationary die stamping means 2 3 and movable die stamping means 24 arranged for stamping out therebetween pieces of material from strips of material fed to the punch press. The movable stamping means includes a ram 25 adapted to be reciprocated vertically along the ways or gibs 26 by means of the rod 21 and the ball 28 mounted in the socket 29 in the said ram, said rod 21 being connected to the crank shaft. Secured to the face 30 of said ram is a die set 3! and secured to the face 32 of the die set is a die pad 33. As shown in Fig. 3, the die pad 33 is provided with a pair of depending punch members 34 which may be of any suitable size and form desired for performing a certain stamping operation on the material fed to the press.

The stationary stamping means 23 is mounted upon the table 35. Said means includes a base member 36, a shim 31 mounted on the base 38, a die set 38 secured on the shim, and a cap 39 secured to the shim 37. Openings 48 are provided in the cap 39 and die set 38 for receiving the depending punch members 34 upon the downward stroke of the ram 25 to perforate, for example, the strip of material Al. The lead pins :22 mounted between the base 36 and the die set serve also to guide the vertical reciprocal movement of the movable die stamping means 24.

The construction of the punch press 18 herein above described is well known in the art, it being understood that the construction of the punch press It per se is not intended to form a part of this invention. By the same token, it is not intended to be limited thereby, but as will become apparent hereinafter the automatic punch press stopping mechanism embodying the invention is adapted to be applied to punch press machines of any suitable form, size or construction.

It will be understood that punch presses of the character herewith concerned are devised to perform successive operations upon successive portions of the metal strips fed to the press. In operation, such presses are run at continuous speeds and often are set and left to run unattended. It is necessary therefore to provide a stopping mechanism for stopping the press when any abnormal condition occurs, such as jamming or misfeeding of the metal strip in the press.

The automatic stopping mechanism constituting my invention operates to stop the reciprocating motion of the movable stamping means 24 in one complete stroke in the event material going through the die set 38 misfeeds or becomes jammed inside said die. Generally, in the event of a jam or misfeed in the die 38, when the ram 25 comes down on its downward portion of a complete stroke, there is provided a guide pin on the die set 3! which comes in contact with the jammed or misfed strip of metal in the die 38. The pin upon striking the jammed metal is caused to move upward, the upward movement of the pin being transferred by means of cam action and a push rod to a spring action cylinder housed and secured to the die set 3|. By the time the ram 25 completes its full downward stroke, the movement of the cylinder depresses a hydraulic piston. The movement of the piston is transferred hydraulically to a second piston, the movement of the second piston being adapted to engage and trip a spring loaded lever member. Movement of the lever member results in release of the footoperated treadle I6, which in turn actuates the pull rod 15 connected to the clutch It for stopping the reciprocating movement of the ram 25 at the top of the stroke. It will be apparent that by means of such automatic stopping mechanism the punch press is prevented from entering upon the next succeeding stroke once the guide pin thereof comes in contact with a strip of material which is jammed or misfed in the die 38. The press !0 may then be cleared for normal operation. I also provide means for engaging the treadle I6 for keeping the treadle in a continuously depressed condition for operating the machine IQ at continuous high speed. The automatic stopping mechanism is adapted to release said means for preventing succeeding operation of the press in the event of jamming or rnisfeedmg.

Referring now to the drawings wherein a preferred embodiment of the automatic stopping mechanism embodying the invention is shown, the die set 3| is provided with a cylindrical bore 45 adapted to be closed at its upper end by a removable plug it. The lower end of the bore is adapted to receive therein a guide pin d8, said pin 438 being movable vertically in said bore. The pin 48 includes an elongate rod portion 549 and an enlarged diameter portion 59 seated in the bore. The portion 58 is provided with a central recess 5! and in order normally to bias the said pin downwardly as Viewed in Fig. 3, there is provided a coil spring 52, said spring having one end thereof engaged against the bottom wall 5 of the recess 5! and its other end 55 engaged against the plug 46. The portion 58 is annulariy shaped and includes an inclined shoulder portion 55 of a diameter less than that of the bore 15.

The shoulder portion 56 is in the nature of a cam surface and is arranged to engage the end 51 of a horizontally disposed push rod 53 housed in the horizontally disposed bore 53 provided in the die 3|. The second end 59 of the rod 58 has an integrally formed boss thereon, which boss 68 is disposed in the casing 6! attached to the die 3| by long screws 52. The casing 8! includes an upper wall 63, a lower wall 64 and a pair of spaced-apart vertical walls 65 and 63 to which the walls 63, 64 are secured by means of the screws 61. There is thus formed between the walls 65 and 86 a vertically extending bore 68 in which is housed for vertical movement a spring action cylinder 69. The cylinder 65 is shorter than the length of the bore 68 thereby permitting substantial vertical movement in said here.

The cylinder 69 has a vertically extending recess la in the top portion thereof adapted to receive therein a coil spring H. The spring '1' l is arranged normally to bias the cylinder 69 downward, said spring having its lower end engaged against the bottom wall 13 of the said recess it and its other ends engaged against the inside surface of the wall 63. A pin i5 is slidably mounted in a groove i2 on the inside surface of wall 66, said pin extending into a recess 18 in cylinder 69 between wall 13 and wall it. A short, slidable, rod '56 has one end thereof engaged against boss 5!) and its opposite end extending into the recess it spaced from pin 75. A spring I3 is disposed between rod "it and i5 in said recess and is arranged normally to bias rod It outwardly from recess 'Et' against boss BEE. In this normal position, rod will have a portion l! protruding from cylinder @9 which portion acts as a. stop member. The portion i1 abuts the shoulder l9 on wall t5 and this position prevents cylinder 89 from moving downwardly under the bias of spring li. Referring to Fig. 3, when rod 58 is moved to the right as guide member 38 is moved vertically, the boss til will move portion T! to the right free of shoulder 'E'S thereby per mitting spring H to urge the said cylinder downwardly in bore 68. ihe pin IE will ride in groove I2 along with said. cylinder. Upon return of the cylinder, as rod it passes shoulder '59, spring is will urge into position engaging said shoulder.

Mounted on the table 35 by means of a suitable angle :bracs. lid is a piston housing 8| having a central. bore in which is adapted to move a piston bore 82 may be filled with a hydraulic fluid 5 The piston 5:3 is secured to the end 8& of an elongate rod til, said rod being movable in the wall of the said housing. The rod $3 in .rrn is secured to another rod 88, said rod 83 attached to pin 88 secured to bottom wall i of cylinder 59 through wall 64. Movement of the piston 33 will exert pressure upon the hydraulic fluid 8Q.

Mounted within wall of the piston housing 3! is a conventional compression coupling 89 communicating with the bore 82. An elongate tube as is joined to the coupling 39 at one end BI and at its other end 22 to a T-shaped union 93. The arm S ll of said union is threaded within the wall 85 of a cylindrical casing 96 having a central bore 9? adapted to hold therein hydraulic fluid 98. A piston is slidably mounted within the bore 9'1. A push rod see is secured at one end IllI thereof to said piston es, the other end I82 of said piston being disposed within a housing 533 secured on the base II by means of angle brackets and screws H35.

The housing .33 is provided with means for actuating the treadle it for stopping the press IS in the event of or misfeeding. Said housing its includes a pair of vertically spaced apart walls Hill, a top wall I68 and a bottom wall I59 suitably joined and providing a central cavity H therein. Disposed within the cavity H6 is an elongate push rod Hi provided at its top end H2 with a cap N3, the body of the rod being inserted through the top wall Hi8 and the bottom wall its of the housing 283. Secured on the rod Hi intermediate the ends thereof is an annular disc lit. The rod ill has portions thereof disposed outside of the housing I03, the bottom end 1 i thereof contacting the treadle it. A coil spring lit is mounted over the rod III with one end II! engaged against the inside of the wall 55% and its other end H8 engaged against the bottom surface of the disc IM.

Mounted on the wall i9 5 and extending within the cavity its is provided a stud shaft I20. The end ml of said shaft is pivotally secured to a plate member E22. The member I22 is provided with a hook E23 adapted to engage the top surface E26 of the disc lid and a straight portion I which is disposed against the end 102 of the rod I00. The member !22 is considerably shorter than the rod Hi and. is arranged so that when the hook I23 is engaged with the disc lid, the spring H5 will be compressed whereby normally to urge the rod HI upward out of contact with the treadle it when released. A spring {25 is secured between the wall its and the hook 523 whereby normally to bias the hook into engagement with the disc I24.

The operation of the automatic stopping mechanism is as follows: The operator controls the starting of the press It by means of the treadle I6. When the treadle It is depressed, the pull rod I5 is carried along therewith and through the linkages 22 causes the clutch It to engage the flywheel I3 for reciprocating the ram 25. Should the operator desire to run the press continuously, he may depress the cap I I3 moving the rod III downward against the treadle I6. The hook 523 will engage the disc IM after the rod III is depressed a sufficient distance whereby to prevent upward movement of the said rod out of contact with the treadle I5.

With the machine in operation the ram 25 is being reciprocated vertically at high speeds carrying along therewith the guide pin it. The material 4| being fed through the die 33 is provided with an opening I39 which is arranged to receive the portion 49 of the pin at on its downward stroke as shown in Fig. 3. Thus, presuming that the material 4| is being fed through the press without occurrence of any abnormal condition such as jamming or misfeeding, the stamping operation of the punch pins 34 will proceed and the guide pin &8 will enter the opening I38 in said material ll without any effect. However, should the material 14 jam or misfeed thereby throwing the opening 539 out of alignment with the guide p n 48, the pin 38 will strike the material 4! on its next downward stroke. Contact with the material will cause the at to be moved upward as viewed in Fig. 3, thereby putting into operation the automatic stopping mechanism to stop the press prior to its next downward stroke.

Upward movement of the pin 48 in the bore 45 will cause the shoulder 55 to ride against the end 5? moving the push rod 58 to the right a distance corresponding to the width of the shoulder 56. Movement of the rod 356 will push the rod 76 against the spring I8 and move portion TI free of shoulder 79 thereby freeing the cylinder 69. The spring II will then bias the cylinder downward moving the pin 88, rod 83, the rod 86 and the piston 83 whereby to exert a pressure on the hydraulic fluid B2. The pressure thus exerted on the fluid 82 will be translated through the tubing 93 to the hydraulic fluid 93 in the casing 96 and thence against the piston 99. The piston 99 will be moved to the left as seen in Fig. 3, pushing the end I02 thereof against portion I25 of the member I22. The member I22 will then be pivoted clockwise causing disengagement of the hook I23 from the disc I I4. Upon release of the hook from the disc the spring I 56 will urge the rod III upward out of engagement with the treadle I6. The treadle I6 will then also be urged upward by means of the spring I8 causing the pull rod I5 to be moved upward. The upward movement of the rod I5 will be translated through the linkages 22 to the clutch I4 to stop the machine It). It will be noted that the stopping of the press I0 is accomplished before the next succeeding downstroke after occurrence of a jam of misfeed in the die 38.

My stopping mechanism above described is adapted for use with an electrical starting and stopping mechanism such as shown in Fig. 5. The tubing 92 is there shown joined to the T- shaped union 93 and the arm 94 thereof is joined to a casing 96 such as previously described. The casing 96 is supported by a bracket I3I secured on the press II]. There is shown the end I32 of a slidable member (not shown) mounted within the casing 96 and adapted to be moved hydraulically in a well-known manner. The end I32 is disposed in engagement with a push button I33 of a switch I34 connected into an electrical circuit for stopping and starting the press it. The end I32 normally is biased away from the button I33 by means of a spring I35 mounted over the same, one end of the spring being biased against an annular shoulder I36 on the said end and the other end of the spring being biased against the switch I34. Upon the occurrence of an abnormal condition in the die 38, the upward movement of the guide pin 48 will result in the end I32 of slidable member being moved by hydraulic pressure against the push button I33 to open the switch I34 and stop the press. Again, the automatic stopping action of my mechanism may be vantages should readily be understood from the foregoing without further description, and it should be manifest that while a preferred embodiment of the invention has been shown and described for illustrative purposes, the structural details are nevertheless capable of wide variation within the purview of the invention as defined in the appended claim.

What is claimed and desired to be secured by Letters Patent of the United States is:

In a punch press of the character described and having a reciprocating die head, a stationary die bed, a conventional driving and re-cycling mechanism for said press, said press having a continuous strip of metal passing over said bed for operation of the die head on successive portions thereof with successive reciprocations of the die head, a control mechanism including a spring biased treadle member connected to said driving mechanism for operating same and being continually urged to a press stop position, a push rod arranged to move the treadle to a position causing operation of the driving mechanism and means thereafter locking the push rod in a position resulting in re-cycling of the press, an automatic stopping mechanism for stopping the press in the event said strip becomes misaligned relative to the die head comprising a movable guide member housed in said die head, spring-action means adapted to be mounted on the head in operative association with said guide member and a hydraulic fluid system connected between said spring-action means and treadle locking means, said spring-action means adapted to actuate the hydraulic system to release the treadle locking means to permit movement of the treadle to press stop position and comprising a casing adapted to be secured to said die head, a springbiased cylinder movably disposed in the casing and operatively connected with said system, a movable stop member adapted to maintain the cylinder immovable against the bias of said spring, said stop member being operatively connected with said guide member and arranged to be moved thereby free of the cylinder whereby said cylinder may be biased to move causing a pressure to be exerted through said hydraulic system for stopping the press.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,139,773 Kent May 8, 1915 2,028,631 Stevens Jan. 21, 1936 2,134,933 Smith Nov. 1, 1938 2,366,960 England Jan. 9, 1945 

